PubMed Health⌕ Search

Biomedical subjects

S Bergström

Publications and source records attributed to S Bergström.

At least 145 records · Page 8Linked to original sources
PubMed1994

A family of surface-exposed proteins of 20 kilodaltons in the genus Borrelia.

Relapsing fever and Lyme disease spirochetes of the genus Borrelia display at their surfaces abundant lipoproteins: Vmp proteins in Borrelia hermsii and Osp proteins in Borrelia burgdorferi. Vmp and Osp proteins largely determine serotype specificity, and neutralizing antibodies of infected or immunized animals are directed at them. For the present study, we examined B. hermsii serotype 33, which is unique among strain HS1 serotypes in the low frequency of switches to other serotypes during infections and in vitro cultivation. Failing to clone the complete vmp33 gene, we accomplished its further characterization by (i) determining three partial amino acid sequences, (ii) designing oligonucleotide primers based on these amino acid sequences, (iii) cloning and sequencing the central portion of vmp33, and (iv) using outwardly directed primers and the inverse PCR to clone the 5' and 3' ends of the gene and flanking regions. The transcriptional start site was identified by primer extension analysis. Vmp33 was a polypeptide of 211 amino acids; the three partial amino acid sequences were identified in the open reading frame. Vmp33 was found to be more similar to other 20-kDa Vmp proteins of B. hermsii and to OspC proteins of B. burgdorferi than it was to 35- to 39-kDa Vmp proteins of the same strain. Moreover, OspC proteins were more similar to Vmp33 than they were to OspA, -B, or -D proteins of B. burgdorferi. These sequence similarities were consistent with Western blot (immunoblot) findings of cross-reactions between Vmp33 and OspC with anti-Vmp33 and anti-OspC sera. The promoter for the expressed vmp33 gene was found to be different from the expression site for other active vmp genes characterized to date. These results indicate that Vmp33 and other small Vmp's belong with OspC to a genus-wide family of 20-kDa proteins and that expression of these proteins may be coordinated with expression of other Vmp and Osp proteins in Borrelia spp.

Amino Acid Sequence↗
PubMed1994

Identification of a highly cross-reactive outer surface protein B epitope among diverse geographic isolates of Borrelia spp. causing Lyme disease.

The outer surface lipoprotein B (OspB) of Borrelia burgdorferi is a major component of the borrelial protein profile and has been shown to be highly immunogenic in experimentally immunized and infected mammals. However, the ospB loci of different strains show considerable heterology at the nucleic acid sequence level, and the progeny of a clonal strain of B. burgdorferi exhibited OspB polymorphisms with respect to apparent molecular weights and reactivities with monoclonal antibodies. These data suggest that OspB is not a good candidate for vaccination or diagnostic purposes. The present study describes a monoclonal antibody, designated 84C, directed against a very highly conserved domain of the OspB lipoprotein. Western immunoblot analysis with 84C demonstrated reactivity in 84.2% of human, tick, and other vertebrate isolate strains examined from widely diverse geographic regions, including strains of B. burgdorferi sensu stricto and two closely related species, B. garinii and B. afzelii. The 84C-binding region was delimited to a highly conserved 11-amino-acid region in the carboxyl terminus of OspB as demonstrated by (i) DNA sequence analysis of wild-type and 84C-resistant mutant ospB alleles and (ii) deletion mutagenesis of a recombinant ospB gene in Escherichia coli. Finally, the 84C epitope was demonstrated to be exposed on the borrelial surface in situ as (i) the monoclonal antibody 84C was able to agglutinate borrelias in culture and (ii) 84C-resistant escape variants were isolated. These data suggest that the potential value of OspB as a vaccine candidate or diagnostic tool be examined more closely, in the context of the 84C-reactive domain.

Amino Acid Sequence↗
PubMed1994

Value of symphysiotomy in obstructed labour management and follow-up of 31 cases.

Experience of 32 cases of symphysiotomy carried out in Mozambique and in Botswana is reviewed. Of all cases only 1 was lost to follow-up. The observation period varied from 7 days to 6 months. Among 31 cases examined at discharge or on return from check-up few complications occurred. Vaginal laceration occurred in 3 cases, haematuria in 1 case and wound infection in 1 case. In 2 cases there was significant postoperative pain causing gait problems, but in no case were there significant problems with pain at discharge or at follow-up. It is concluded that the intervention is seldom complicated by severe sequelae, provided strict adherence to given indications is respected. In rural areas in the third world symphysiotomy is a life-saving and simple surgical intervention, which should be regarded as an adjunct measure in some cases with a moderately contracted pelvic outlet incompatible with normal vaginal delivery.

Botswana↗
PubMed1994

Obstetric implications of rhesus antigen distribution in Mozambican and Swedish women.

AB0 and Rhesus phenotypes were analyzed in 199 Mozambican women and the gene frequencies were calculated. The frequencies of the K and Fya antigens were also investigated. The findings were interpreted against the background of the corresponding phenotype distribution of a Swedish population. D- and Du-positive women amounted to 97.0%, which is significantly more than in Sweden (p < 0.001). Among AB0 groups it was found that blood group 0 is significantly more predominant in Mozambican than in Swedish women (p < 0.001). The reverse is true for blood group A (p < 0.001). Blood group B has a similar prevalence in Mozambican and Swedish women. The obstetric implication of the low prevalence of D-negative women is that the Rhesus alloimmunization problem may be of a much smaller magnitude than would be expected.

ABO Blood-Group System↗
PubMed1994

Audit of uterine rupture in Maputo: a tool for assessment of obstetric care.

Records of 96 women who had rupture of the uterus in labor were audited to find circumstances significantly associated with pregnancy outcome. The prevalence was 1 rupture in 424 deliveries. In 74 cases (77.1%) uterine rupture occurred after hospitalization, the remaining 22 cases being emergency transfers with rupture secondary to a delivery attempt elsewhere. History of a previous cesarean section was present in 46%, whereas 54% of the women had an unscarred uterus. Maternal mortality was 7.3% whilst perinatal mortality was 62.9%. Adverse outcome for the mother was associated with ruptures occurring in unscarred uteri (p < 0.02) and outside the Maternity (p < 0.01); this latter condition also contributed to higher fetal mortality (p < 0.002). The findings confirm that delay in reaching medical care is an aggravating factor in the evolution of uterine rupture in developing countries and suggest the need for better medical attention and timely diagnosis in laboring women with unscarred uterus.

Adolescent↗
PubMed1994

Risk factors in puerperal endometritis-myometritis. An incident case-referent study.

Postpartum endometritis-myometritis (PPEM) was identified in 51 women after vaginal delivery, who were compared with 51 healthy referent parturients, matched for age, parity and days postpartum. Socio-economic background data, past and current obstetric history and clinical data from recent delivery were analyzed. Endocervical and intracavitary cultures and blood cultures were performed and serological analyses of syphilis and HIV antibodies were carried out. No socio-economic factor studied discriminated significantly between cases and referents. Previous stillbirth (OR 9.44) and previous low-birthweight delivery (OR 3.90) occurred significantly more often among cases. In recently past pregnancy preterm delivery (OR 10.07), low birthweight (OR 16.55) and serious neonatal morbidity (OR 14.27) were significantly more common among cases. Cases and referents differed also significantly in body mass index < 22.5 (OR 3.41), left mid-upper-arm circumference < 25 cm (OR 2.66), haemoglobin < 100 g/l (OR 3.12) and high-risk classification in antenatal care (OR 11.95). Bacterial intracavitary cultures tended to be positive and have anaerobes more frequently in cases than in referents. It is concluded that women with PPEM in the setting studied belong to a group at risk also regarding adverse fetal outcome, both in recently past and in previous pregnancies.

Adult↗
PubMed1994

An incident case-referent study of stillbirths at Harare Maternity Hospital: socio-economic and obstetric risk factors.

This incident case-referent study was conducted at Harare Maternity Hospital in 1989-1990 on 104 consecutive cases of stillbirth with unknown aetiology and 96 age- and parity-matched referents. Information was collected by interviewing the women following a standardized form and by review of antenatal cards. None of the women refused to participate. The most significant obstetric risk factors were prevalence of earlier stillbirths (odds ratio, OR = 6.1) and miscarriages (OR = 4.8). Low height and body mass index also increased the risk of having a stillborn baby significantly as well as a history of flue-like illness during pregnancy (OR = 4.6). The latter may have stimulated the women to book early causing the unexpectedly high OR for early booking among these cases. The pattern for the socio-economic risk factors was not easy to interpret. The most striking finding was the U-shaped relationship between socio-economic status and stillbirths with a higher risk among those with low and high status.

Adolescent↗
PubMed1994

Isolation of mRNA and genomic DNA from epithelial cells in human milk and amplification by PCR.

Studies on the regulation of human milk protein genes and suitable cell culture systems have been limited due to restricted availability of tissue samples from lactating women. Although mammary gland tissue has been available from mammary reduction surgery, studies on tissue-specific expression of milk protein genes require samples obtained during specific stages of expression in the tissue, i.e., lactation. We have therefore developed a technique to isolate mRNA and genomic DNA directly from epithelial cells isolated from human milk and used PCR methodology to specifically amplify the cDNA and genomic DNA for human beta-casein. When comparing fresh human milk with milk that has been stored for five hours at 37 degrees C or frozen and thawed, we found that the amount of mRNA isolated was considerably higher from fresh milk. However, in spite of this, we could still isolate intact mRNA from frozen milk. The described methodology should be useful in studies on milk protein gene expression during lactation and studies on variants of milk protein genes.

Base Sequence↗
PubMed1994

Application of vaginal misoprostol before cervical dilatation to facilitate first-trimester pregnancy interruption.

OBJECTIVE: To study the capacity of vaginal misoprostol to soften the cervix and facilitate cervical dilatation in women undergoing first-trimester pregnancy interruption. METHODS: We performed a double-blind, placebo-controlled study in 100 women opting for voluntary pregnancy interruption. The subjects were randomly allocated to two treatment groups, receiving either 200 micrograms misoprostol or placebo in the posterior vaginal fornix 6 hours before cervical dilatation. We noted the number of women with vaginal bleeding, with chorionic tissue in the vagina, or with no resistance to a Hegar 8 dilator, and recorded the total time in minutes for pregnancy interruption. RESULTS: Vaginal bleeding from the cervix occurred in 70% of the misoprostol group and in 8% of the placebo group (odds ratio 26.83; 95% confidence interval [CI] 9.73-74.00). Almost one-fourth (22%) of the misoprostol-treated women had chorionic tissue in the vagina, compared to one woman (2%) in the placebo group (odds ratio 13.82; 95% CI 2.59-73.61). Cervical dilatation was achieved in 74 and 10% of the misoprostol- and placebo-treated women, respectively (odds ratio 25.62; 95% CI 9.61-68.28). The time required for pregnancy interruption was significantly shorter with misoprostol (P < .004). CONCLUSION: Misoprostol is significantly more effective in facilitating cervical dilatation than is placebo. The average intervention time for pregnancy interruption was reduced by 35%.

Abortion, Induced↗
PubMed1993

A Lyme borreliosis cycle in seabirds and Ixodes uriae ticks.

The Lyme disease spirochaete, Borrelia burgdorferi s.l., is the only Borrelia known to infect both mammals and birds. The main vertebrate reservoirs of B. burgdorferi are thought to be various small and intermediate size mammals, but the importance of birds as a reservoir has not been thoroughly explored. In the Northern and Southern Hemispheres the seabird tick, Ixodes uriae, is prevalent and closely associated with many species of colony-nesting marine birds. Here we report the presence of spirochaetes, demonstrated by immunofluorescent assay, by polymerase chain reaction and in culture, in I. uriae infesting razorbills on an island in the Baltic Sea. This island is free from mammals. The protein profile of the spirochaetes and the sequences of their flagellin and ospA genes are identical to those of the Lyme disease spirochaete, Borrelia burgdorferi s.l., previously isolated from I. ricinus on a nearby island. In biopsies from the foot web of razorbills, B. burgdorferi-specific DNA was detected after amplification by polymerase chain reaction. Our results suggest that birds play an important part in the maintenance of B. burgdorferi and that mammals may not be a prerequisite for its life cycle.

Animals↗
PubMed1993

Coxsackie B virus infections in women with miscarriage.

To study the possible role of Coxsackie B virus serotypes 1-5 (CBV 1-5) as an etiological factor in miscarriage, 97 women with miscarriage were tested for the presence of CBV-IgM by radioimmunoassays (RIAs) and compared with 113 control women undergoing voluntary interruption of pregnancy in the same gestational week. Of the 80 women with miscarriage before the 13th week of gestation, 34 (42%) had CBV-IgM, whereas 18 of 100 (18%) corresponding control women had these antibodies, a statistically significant difference (P < 0.001). There was no significant difference in CBV-IgM frequency between the women with miscarriage from the 13th through the 27th week and their controls. IgM against CBV 2 predominated, followed by IgM against CBV 5, CBV 4, CBV 3, and CBV 1. Two strains of CBV 5 were used in the RIAs, one (M147) isolated from a woman with miscarriage included in the study and one (V136) isolated in 1971 from a patient with meningitis. When the former strain was used, 13 women with miscarriage and seven control women had IgM, but with use of V136 only two women in each group were IgM positive. CBV 5 was isolated from the placental tissue from more women with miscarriage (6 of 28; 21%), than control women (2 of 21; 10%), but the difference was not statistically significant. No other viruses, except cytomegalovirus from a woman with miscarriage, were isolated.

Abortion, Spontaneous↗
PubMed1993

Expression of human milk beta-casein in Escherichia coli: comparison of recombinant protein with native isoforms.

Studies on physiological function and on structure-function relationships of human milk beta-casein have been limited. In this study, we have introduced the human beta-casein cDNA into vectors designed for expression in Escherichia coli. The inducible T7-based expression system resulted in high-level expression of recombinant beta-casein. The recombinant beta-casein, localized intracellularly in E. coli, was purified to homogeneity and compared with purified native beta-casein, in particular with respect to phosphorylation. The E. coli-produced beta-casein was found to comigrate with the full-length, nonphosphorylated native human beta-casein isoform on SDS-PAGE. An N-terminal peptide containing all tentative phosphorylation sites was isolated from the recombinant protein and analyzed by mass spectrometry. The molecular mass as well as the migration of this peptide on reversed-phase chromatography confirmed that it was unphosphorylated.

Amino Acid Sequence↗
PubMed1993

Obstetric characteristics in parturient women with newborns dying during the first 24 hours of life in Maputo.

A case-control study of parturient women with newborns dying during the first 24 hours of life was undertaken at the Maputo Central Hospital. A total of 36 such parturients were recruited on a consecutive basis. For each case woman two referent women randomly selected among parturients with newborns surviving the first 24 hours of life were recruited. Parturients suffering neonatal loss had, in relation to their referents, a similar number of previous pregnancies but significantly fewer surviving children, lower average gestational length, lower average fundal height at birth, longer duration of membrane rupture, fewer normal, cephalic vaginal deliveries, and much lower birthweight. Parturient women suffering from early neonatal loss in this setting represent a more vulnerable segment of the population than their referents. Their newborns suffer from a shorter gestational length and from a more prolonged duration of membrane rupture than newborns from referents.

Birth Weight↗
PubMed1993

Prevalence of syphilis infection in Mozambican women with second trimester miscarriage and women attending antenatal care in second trimester.

OBJECTIVES: To elucidate whether recent syphilis infection is significantly more prevalent among women with mid-trimester miscarriage than among antenatal care attenders in midtrimester pregnancy. DESIGN: Two categories of pregnant women were compared regarding serological signs of syphilis. Rapid Plasma Reagin (RPR) analyses were done in Mozambique and Veneral Disease Research Laboratory (VDRL) tests in Sweden. In case of RPR and/or VDRL positivity, Treponema pallidum haemagglutination (TPHA) and Captia Syphilis-M were performed. SETTING: A suburban antenatal care clinic and the emergency ward at the Department of Obstetrics and Gynecology at the Central Hospital in Maputo, Mozambique, were studied June-August 1991. SUBJECTS: Randomly selected women seeking antenatal care in midtrimester pregnancy (N = 202) were compared with 114 women consecutively entering with clinical signs of midtrimester miscarriage. RESULTS: Among antenatal care attenders, 37/202 (18.3%), and among women with midtrimester miscarriage, 37/114 (32.5%), had syphilis confirmed with the Treponema pallidum haemagglutination test (p < 0.01). Significant titres of IgM antibodies tended to be more prevalent among women with miscarriage (7.0%) than among women attending antenatal care (4.5%), though the difference only approached statistical significance. CONCLUSION: The findings suggest a potential association between syphilis seropositivity and midtrimester miscarriage. Present findings justify more extensive studies to establish whether or not recent syphilis infection is a risk factor for midtrimester miscarriage.

Abortion, Spontaneous↗
PubMed1993

Pregnancy interruption by vaginal misoprostol.

A total of 132 pregnant women with average gestational age of 14.2 weeks (range 11-22 weeks) undergoing legal abortion volunteered for a trial utilizing vaginal administration of misoprostol. In 106 women a dose of 800 micrograms was utilized, whilst in 26 women 1,200-1,600 micrograms were given. Nonsurgical expulsion of the fetus was successful in 117 cases (88.6%). Four cases had to be excluded for various social reasons. A total of 11 did not achieve fetal expulsion within 56 h after application of misoprostol. These cases (11/132; 8.3%) were considered failures. Previous reports in the literature of toxicity trials on animals reporting no fetotoxic nor teratogenic effects of misoprostol at doses up to 10,000 micrograms/kg body weight seem to be of no validity in the human since we could demonstrate that almost 80% of pregnancies were interrupted at a dose of 10-15 micrograms/kg body weight. The conclusion is that vaginal administration of this prostaglandin analogue, not requiring cool temperature for storage, is remarkably effective in achieving safe interruption of pregnancy without any significant complications.

Abortion, Legal↗
PubMed1993

Value of perinatal audit in obstetric care in the developing world: a ten-year experience of the Maputo model.

A decade of perinatal audit in the Maputo Central Hospital is reviewed with the objective of addressing the potential value of the audit process in monitoring the different constituents of morbidity and mortality in the perinatal period. The perinatal mortality showed a significant but transient change during the observation period 1982-1991, while intrapartum fetal mortality was significantly reduced from 10.9 to 3.9 per thousand (p < 0.0005). Staff members were sensitized towards immediate and long-term effects of implemented surveillance routines by regular feedback of perinatal data on visible wall charts and by weekly conferences. The advantages of a comprehensive audit approach in perinatal medicine comprising both maternal and fetal/infant aspect are underscored. An ethical commitment to nonconfidential straight-forwardness and open-mindedness in critical discussions regarding mismanagement is emphasized for a successful audit strategy.

Developing Countries↗
PubMed1993

Materno-fetal transmission of pregnancy malaria: an immunoparasitological study on 202 parturients in Maputo.

A total of 202 delivering mothers and their newborns were studied with the intention to follow the materno-fetal transmission of malaria. Malaria infection was encountered in 35 cases (17.3%) in which Plasmodium falciparum predominated in peripheral blood while P. malariae predominated on the placental surface. In cord blood P. falciparum was encountered in 1.5% of the cases. There was slightly more maternal infection in rural (23%) than in suburban areas (19%). Less malaria infection was encountered in primiparas than in multiparas and there was similar antibody response in both mothers and their newborns. Anaemia was encountered in 70% of the mothers and in 93% of the newborns. There was no significant correlation between low birthweight of the newborn and malaria parasitaemia in the mother.

Animals↗